This invention relates generally to fiber optics and more particularly a switching device for activating and deactivating optic channels.
A great deal of interest has been shown recently in optical communications. This method has many advantages over conventional wire type communications including among others, channel isolation. This particular feature eliminates cross-talk and allows fiber optics to be bundled closely in cables or the like.
Because of the channel isolation feature, optical fibers are particularly well suited for secure communications. However, if used for secure communication, optical fiber systems must have switching systems which will fully attenuate light and not allow any leakage.
One of the concerns that arises with fiber optics is a natural loss or attenuation in the switching matrix. Light loss per switch in the system must be negligible since, with the large number of switches that light must pass through, substantial light loss in each would ernder the system ineffective. Some switches presently available use a doping process to increase the index of refraction to create the light guiding channels within the switch, but doped channels are normally lossy as well as slightly leaky. Others in which light is guided in a region bounded by a lowered index of refraction created by application of an electric field to the boundary regions, while not lossy, are still leaky particularly at discontinuities. Such leakage can enter another channel creating crosstalk.